All things considered this is a great episode. Many loose ends were tied up. And it moved along at a brisk pace. No time for boredom and no point in reiterating observations made by others during the episode review on Podshock. But I will make a few observations that weren't made during the review.

At the 18 minute mark we see the Doctor looking at River in an Apollo Space Suit. See photo for it depicts that precise moment. Notice that the Doctor's hair is parted on the left side of his head. In the very next shot we see his face reflected in the gold outer sun visor of River's helmet... or do we? Actually we see an image of Matt Smith's face superimposed onto River's gold visor, but it isn't his reflection because the part in his hair is still on the left side of his head.

Area 51 is supposed to be a well kept secret, so why is Area 52 so boldly emblazoned on the side of a pyramid? Because we forget The Silence when we look away from them. Painting up Area 52 is the same as marking yourself each time you have a Silent encounter. A simple subtitle on the screen could have alerted us to our whereabouts once we were inside the pyramid, but this is much bigger than knowing where we are, rather, it is about knowing where The Silence are, more to the point, that they are amongst us.

During the review Dave rightfully questioned the practicality of the suits worn by The Silence, indicating that they would lose whatever they had in their pockets when they hung upside down from the ceiling. I doubt that The Silence ever use their suit pockets given the size of their digits. I mean, how would you put anything in or remove anything from a pocket that's smaller than one of your fingers?

The fact of fiction is that Ray Cummings, an early writer of science fiction, wrote in 1922, "Time is what keeps everything from happening at once", a sentence repeated by scientists such as C. J. Overbeck, and John Archibald Wheeler.

Despite the silliness of a machine such as a clock standing still because time is standing still, which if you think about it is really quite absurd, time stood still in this episode, and as long as it did, everything happened all at once.